Rep. Roscoe Bartlett, who is facing a competitive election in November, was one of 19 House Republicans on Tuesday to oppose legislation that would ease environmental regulations for border agents working in federal parks.

The legislation, which ultimately passed the GOP-led House on a 232-188 vote, would waive certain environmental requirements for U.S. Customs and Border Protection agents. Environmentalists have raised concerns about road building and other construction in land otherwise protected from development. Supporters of the bill say illegal immigrants have used the sparsely populated areas to cross the border.

"I received hundreds of requests just today and by a three to one ratio, constituents who contacted me urged me to oppose [the bill] because on balance, they believe this bill will do more harm than good to our national public lands," Bartlett said in a statement.

The decision to break with Republican leaders also comes as Bartlett is running for an 11th term in a new district that was drawn to be more friendly to Democratic candidates. He faces Potomac businessman John Delaney in November.